YA horror book where children are turned into bugs

[[deleted user]]

Trying to find a book I read a few years ago, I think it was YA horror where you follow a few children at a boarding school where some mysterious bug like thing exists, when it touches you, you become one of the bug like things. it eventually culminates in them locking themselves in the school and boarding themselves up until finally a few of the children manage to escape on a helicopter.
The bug is some type of roach like thing if i recall correctly

[Becca]

The Cavendish Home for Boys and Girls by Claire Legrand?

[[deleted user]]

Becca wrote: "The Cavendish Home for Boys and Girls by Claire Legrand?"
nah they turn into like roach like things